


Shapeshifter

by Nikolaus_Chaser



Category: Supernatural
Genre: Alpha Dean, Alpha/Beta/Omega Dynamics, Canon-Typical Violence, Case Fic, Fluff and Angst, Hurt Castiel, Hurt/Comfort, M/M, Mpreg, Omega Castiel, Schmoop, mentions of mpreg
Language: English
Status: Completed
Published: 2016-10-20
Updated: 2016-10-20
Packaged: 2018-08-23 13:19:17
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,588
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8329387
Author URL: https://archiveofourown.org/users/Nikolaus_Chaser/pseuds/Nikolaus_Chaser
Summary: There is a shapeshifter on the loose that has been stealing the identities of mated Alphas so that he can prey on their Omega mates.  Dean decide to go after him, but he doesn't want Castiel to come along.





	

The snarl that rises in Dean’s throat is muffled by the clothe that’s been stuffed in his mouth, tied around his head as tightly as the coarse ropes that bind his wrists to the radiator behind him.  His nostrils flare, eyes growing dark and red as he watches his captor stalk towards him.  She’s a tall woman with a pointed jaw and narrow eyes, her long brunette hair tied into a neat bun atop her head.  A sick smirk spreads across her lips as she stalks closer, heels clicking against the floor, her eyes flashing silver as she crouches down in front of Dean.

“What a strong Alpha you are,” she purrs, reaching out and pawing at Dean’s chest, her long fingernails dragging over his pectoral muscles.  He snarls again, lips curling up in disgust as he bares his teeth and fights against his restraints.  The woman chuckles, a sick sound, and she lets her nails dig into Dean’s chest as she pushes him back against the wall.  Her strength is surprising, and she controls Dean easily as he continues to snarl and gnash his teeth at her.  “I wonder what your sweet Omega would see if he saw you here now, bound and at my mercy.”

At the mention of his mate, Dean lashes out again, jerking forward and tugging with renewed vigor against the ropes that retrain him.  The woman smiles, her fanged teeth extending as she throws her head back in a laugh.  Dean glares at her, and her hands resume their path down his body, towards his waistline and over the hem of his pants.  His squirms, heart hammering in his chest as she reaches around his body and dips her hands into his back pocket.  She pulls his cell phone from his back pocket, swiping it unlocked.  Dean growls.

“Is this your mate?  Cas?” She asks, fingers skittering over the phone screen as she begins to type.  Dean’s answering growl is all the confirmation that the woman needs, and she smiles devilishly at the phone.  “Oh, how sweet.  He’s worried about you.  Says that he _misses_ you.”  She laughs, setting the phone into her own back pocket and leaning forward, so close to Dean’s face that her breath ghosts over his own lips.  It wreaks of blood.  “How do you think he would like for you to pay him a little visit?”

Dean’s nostrils flare, and his eyes narrow at the woman as she raises her hand, cupping his bare cheek with her palm.  Her sharp fingernails skate over his cheek and he whimpers, watching before his eyes as the woman’s skin begins to ripple and darken.  Her bones shift beneath her skin, her features growing more masculine, and Dean watches in disgust as her very shape transforms from that of a woman into a man.  Into a man who looks exactly like Dean, more specifically, and the Alpha feels as if he could vomit.

“This should be fun,” his double announces once the transformation is complete, eyes shining silver for just a moment as he cracks his knuckles and stands up again.  Dean begins to snarl again, fighting against his restraints, and the shapeshifter casts one last smirk in his direction as he turns and begins to walk away.  “I’ll make sure to tell Cas that you said hello.”

₪₪₪₪₪₪₪₪₪₪₪

“Dean, is that you?”  Castiel’s voice carries from the bunker kitchen a moment after the shapeshifter closes the door, and he waits a moment before clearing his throat and calling back to the Omega.

“Yeah, babe.  I’ll be down in a minute.”

Dean’s double takes a moment to school himself, to think through what he’s about to do and say before he shrugs his coat off his shoulders, hangs it up in the coat hook by the door and then makes his way down to the war room.  He looks around curiously as he steps into the vast room, eyes traveling over the vast display of weapons and books that are housed on the shelves all around the room. 

So this is what a hunter’s home looks like.  Huh.

“Dean?” The same voice from before brings the shapeshifter back to attention, and he whips his head towards the doorway, where a handsome Omega is leaning against the doorway and looking at him curiously.  So this must be Castiel. “You alright there, Little Alpha?”

“Huh?  What.  Yeah.  Just missed you, is all,” the double tries for smooth, and it seems to work, as the Omega smiles sweetly at him and steps forward, wrapping his arms around his waist and nuzzling his neck.  He wraps his arms back around Castiel, dipping his head down and inhaling the Omega’s scent.  He smells like fresh pine and lemons.  It’s pleasant.

“Missed you too.  How’d the hunt go?” Castiel draws back after a few seconds, a look of concern flashing over his face.  Dean shrugs, scratching the back of his neck.

“It went well enough; you know how those things are.  Shapeshifter put up a bit of a fight, but I took care of ‘er.” He smiles, hooking his thumbs into his front pockets.  Cas nods slowly, then turns and glances back towards the kitchen.

“Alright.  Well, you’re home a little early, so dinner won’t be ready for a few hours yet.  I wasn’t expecting you until tomorrow night, I thought you and Sam were going to meet up for that salt-and-burn in Great Bend, then head back home together.”

“He called me, said he’d take care of it on his own.  He mentioned he’d be heading north to pick up a case with Rudy, I think he said somethin’ about a werewolf in Danbury,” he smiles, reaching out to pull Cas in close, nosing purposefully at his neck.  “Which means we’ve got the whole weekend to ourselves.”

Castiel smiles and laughs, playfully shoving at Dean’s chest.  “Get your mind out of the gutter, Dean.  We have work to do this weekend.  Plus, Jody and Donna are coming down for a visit on Saturday.  They’re bringing Alex and Claire, and their new pup, so we’re going to have to get three guest rooms set up for them.” He turns, walking out of the room and back into the kitchen.  The shapeshifter scowls as he watches him go, and he’s checking the time on Dean’s phone when he hears the Omega calling to him from the kitchen.

“Dean?  You want a beer?”

“Sure,” he calls back without a second thought, stuffing his phone back into his pocket and ignoring the slew of text messages he’s received from Sam.  Castiel bustles back into the room with two beers in hand and a smile on his face.  They are both popped already, smoke rising from the top and foam bubbling at the lip of the bottle.

“So you killed the shapeshifter, then?” Castiel asks as he takes a sip from his own drink, leaning back in his chair and eyeing Dean up and down.  “What was she killing people for anyway?  And all Omegas too— was it some sort of hate crime?”

He chuckles.  “Nah.  She was, uh, feeding off of them.  The Omegas.  Takin’ their mates hostage and then coming home dressed up in their meat suits,” he uses the language that Dean had referred to him with when they’d first encountered in his lair.  “It was kinda genius actually.  The Omegas never knew what’d hit them, ‘til it was too late.  A little too eager to trust their Alphas, I guess.”

“Hmm,” Castiel hums thoughtfully, lifting his bottle again and taking a long sip.  The shapeshifter flashes him a small smile, lifting his own bottle to his mouth and taking a gulp.  It burns as it goes down, and he realizes in a moment that this beer must be laced with holy water.  Castiel watches him curiously, but he focuses on swallowing it all down without coughing, and a moment later he sets the beer back down on the table.  Castiel smiles, and he wipes his mouth on the back of his hand.

“Jeez, Dean,” Cas laughs, looking more relaxed than before as he leans in close.  “You were scaring the shit out of me.  Why the hell were you acting so weird?  I thought the shapeshifter had gotten you or something.”

Dean laughs, trying to feign away his nervousness.  His throat is still hurting from the holy water, but he powers through it.  “Sorry, sweetheart.  I’m just tired and all.  Shapeshifter really knocked me around.”

“Hmm,” Castiel bites his lips, standing up and coming around the side of the table.  He settles himself into the imposter’s lap, threading his fingers through his hair and leaning down to kiss him.  The shapeshifter reaches out with his hands to steady the Omega.  “Well, you’re home now.  How about we go head to bed, and I’ll help you unwind a bit?”

Dean’s double smiles.  “I think I’d like that.”

₪₪₪₪₪₪₪₪₪₪₪

Dean grunts with the effort of undoing the ropes that bind him, his wrists already rubbed raw by the coarse rope binding them tightly.  He squeezes his eyes shut, willing himself not to feel the pain as he tears his hand free from the binds, stripping the skin from his wrist in the process.  There will be time for his wounds to heal later; right now, all that matters is escaping this place and getting to Cas.

The shapeshifter left a few hours ago.  Dean knows that he must be halfway to Lebanon by now, if he’s not in the bunker with Cas already.  The thought fills him with a burst of Alpha rage, and he rips his other hand free of the ropes, blood dripping down his arms as he finally manages to stand.  He yanks his gag away, tying it around the wrist that is bleeding most heavily, and then heads for the open window.  This is how he got into the abandoned meat storage facility; it’s how the shapeshifter got out; as far as Dean is concerned it’s the only way to enter and exit the entire building.

He hotwires a car that’s parked down the street from the old building, glad that it’s the middle of the night and nobody is around to see.  The last thing that he needs at this point is for the police to be after him.  His mate’s life is in danger, for Christ’s sake.

Dean’s almost certain that he’s never driven faster in his life.  It’s the middle of the night and the roads are empty, making it easy for Dean to speed down the freeway.  He doesn’t stop, not to sleep or to eat or even to tend to the wounds on his arms.  He’s almost certain that he has a cracked rib from where the shapeshifter kicked him in their scuffle earlier, but he honestly can’t even feel the pain.  All he can think about is Cas.

That bastard shapeshifter stole his phone.  She stole his Impala, too.  She could know anything about him at this point; where he lived, who he was friends with, who he cared about.  She could have visited the bunker already, killed Cas, and now be on her way to take care of Sammy too.  To kill everyone he loved.

Dean was so blind with his anger that he nearly missed the exit for Labanon.  He had to make a dangerous swerve to avoid missing the ramp, and the car nearly flipped over in the process.  He felt his heart pounding in his chest, and he forced himself to focus.  He needed to make it home safe, for Cas.

Terrible visions conjured themselves in his mind, ones he’d only dreamed about in his most terrible nightmares.  Visions played in his mind of Cas’s dead body, bloody and torn to shreds, his limp form hanging in Dean’s arms as the Alpha sobbed over his Omega.  It would be all his fault if Castiel died.  He was the one who’d suggested Cas sit this one out, stay at home where it was safe.  They were trying to start a family, and Dean had been selfish.  He’d wanted Cas to stay away from the action, so that he would know his Omega was safe at home. 

If he’d only come along with Dean on this hunt, they wouldn’t be in this position.  Castiel’s life wouldn’t be in jeopardy right now.

Hopefully his Omega had taken precautions.  Dean knew that Cas was smart, that he could handle himself.  Chances were that he was fretting over nothing.  Cas would have been wise enough to tell that the shapeshifter wasn’t really Dean, he would have given him a test to prove that it wasn’t really him.  They had cases of beer in the fridge that had been treated with holy water; surely Castiel would know to give him some.  He would have realized; would have taken the gun they kept under the table in the war room and shot the shapeshifter then and there.

Dean really didn’t have anything to worry about.

This didn’t stop him from leaping out of the car as soon as he was parked in front of the bunker, sprinting towards the door and forcing himself inside.  The door was unlocked, meaning somebody had forgotten to lock it. 

Cas would never have been so careless.  A feeling of dread filled Dean’s heart as he ran into the bunker, calling out his mate’s name.

“ _Cas!_ ”

A gunshot rang out, crisp and clear, from somewhere in the house.  Dean felt his heart seize and he ran towards the place where the noise had come, his and Castiel’s bedroom.  He drew a pistol from behind one of the bookshelves in the war room, on his way through, and he already had it cocked and loaded by the time he rammed himself into the bedroom.  

The first thing he saw was blood.  A shit ton of it, soaking his and Castiel’s sheets crimson and dripping onto the floor.  The next thing he saw was himself, or at least a person who looked exactly like himself, hanging limply off the side of the bed with a bullet hole in his chest. His mouth hung open, fangs exposed, and Dean felt his blood run cold at the sight.

No matter how many times Dean saw it, it would never cease to chill him when he witnessed himself die.

“You can put your gun down,” Castiel’s voice sounded strained, and it pulled Dean back into reality.  He gasped when he saw his mate, naked from the waist up, a nasty gash in his shoulder that could have only been left by teeth.  A whole chunk of his skin was gone, leaving the tendons exposed, and blood was pouring freely from the wound. He dropped his gun to the floor with a clatter, leaping onto the bed and crawling on top of his mate.

“Cas, honey, oh honey,” he gasped, wrapping a blood-soaked sheet around Cas’s shoulder haphazardly, in an attempt to stop the bleeding.  “I’m so sorry.  I’m so sorry, baby, we’ll get you fixed right up.  Don’t worry.”

“I thought he was you,” Castiel whimpered, eyes squeezed shut from pain and, Dean was sure by the smell of him, humiliation.  “He didn’t smell right, I knew it, but I thought…,” he swallowed thickly, wincing in pain as Dean forced him to sit up.  More blood flowed from his shoulder; they needed to get Castiel to a hospital.  “I gave him holy water, and he drank it. He didn’t even flinch.  I thought he was you.”

“It’s okay, baby, it’s okay,” Dean breathed, trying and failing to get Cas to stand on his own.  When the Omega’s legs failed him, Dean simply hoisted him into his arms, cradling him like a child as he carried them out of the bedroom.  Cas whimpered, burying his nose in Dean’s chest and willing himself not to cry.  “Just stay with me, alright?  We’re gonna get you to the hospital, and everything will be okay.”

“I love you, Dean.” Cas announced, slipping his eyes closed.  His arm was going numb; his entire body, in fact was going numb.  Dean shook him, and the air filled with his distressed scent.

“No, Cas, keep your eyes open.  _Keep them open!_ ”

Cas laughed, cracking his eyes open, a small smile tugging at his lips even as the world swayed and went blurry around him.  “Hate it when you use your Alpha Voice on me,” he mumbled, though he wasn’t even sure if Dean had heard him.  He felt himself being settled down, presumably in the passenger seat of a car, and he let his eyes slip shut again.  A moment later the car’s engine roared to life, and the last thing that Castiel heard was his mate’s voice in his ear, promising him that he would be alright.

₪₪₪₪₪₪₪₪₪₪₪

_“—bleeding like crazy.  I don’t think I’ve ever seen that much blood in my whole fuckin’ life, Sammy.  It was like… a river of blood.  The doc says he might— might not—”_

_“Dean, he’ll be fine.  He’s Cas.  You know how strong he is.”_

_“I can’t lose him, Sam.  And now, with the baby, I just don’t know how I could deal if it turns out he doesn’t—”_

_“Stop it, Dean.  Don’t even think like that.  Cas is going to make it. He has to.”_

The world is dizzy when Castiel first opens his eyes.  It’s daytime, or at least there’s a whole lot of lights around him, and Castiel’s eyes hurt as they adjust to the brightness.  He can’t help it when he flinches away from the brightness, causing a shock of pain to run up his arm and down his side.  He whimpers, tossing his head to the side and scrunching his nose distastefully.

“Cas?”

That’s Dean’s voice, and the Omega forces his eyes to open for his mate, if only because he thinks he may just be imagining it.  The last time he’d seen his mate’s face, it hadn’t even really been his mate.  It had been a shapeshifter, pretending to be his mate, and he’d attacked Castiel.  He couldn’t remember much after that, aside from the pain, and the fact that he’d somehow managed to grab the gun from under Dean’s pillow and shoot the creature.  He can still remember the look on its face as it died.

But this Dean in front of him is surely alive, and he’s surely not a monster.  He’s Dean’s mate, looking tired and disheveled and so happy to see him, and Castiel smiles, reaching out with his good arm to touch Dean’s face.  The Alpha sighs, leaning close, and nuzzles his scruffy cheek against Castiel’s palm. 

“I missed you.”

Dean laughs wetly, sniffling, and leans closer so that he can press a chaste kiss to Cas’s lips.  The Omega smiles, kissing back, and warmth blooms in his chest.  When Dean draws back, he’s all smiles. 

“I missed you too.  You’ve been asleep for almost two days.  Do you… do you remember what happened?”

Castiel sighs, letting his eyes slip closed.  The light is still bothering him.  “Shapeshifter, tried to eat me.  I shot him.  It all gets a little blurry after that, but I vaguely remember you showing up.  I think you used your Alpha Voice on me,” he cracks his eyes open, squinting suspiciously at Dean.  “You know I hate it when you do that.”

Dean laughs, squeezing Cas’s hands.  “I know, baby.  I’m sorry, but you were slipping away from me.  I was desperate.”

Cas chuckles.  “Yes, well, that’s a new one I think.  An Alpha using their Voice to command their mate not to die.”

“Sounds good to me,” Dean chides, leaning in again to nose at Cas’s neck.  His beard tickles, but Cas doesn’t mind.  He leans closer, enjoying Dean’s scent of leather and ash.  “I was so scared.  I let you down, and if you had died, it would have been my fault.”

“Dean…”

“It would have been, Cas, don’t even argue with me.  You wanted to come on that hunt, and I wouldn’t let you.  If you’d been there with me, he never would have overpowered me.  He wouldn’t have had the chance to get you alone and trick you like he did.  And because of my stupid Alpha posturing, I almost lost you.  I almost lost you and our— our pup.”

“Pup?” Castiel’s voice is small, but hopeful.  Dean looks up at him curiously, resting his cheek on Cas’s chest.

“You didn’t know?” He wonders aloud, letting his hands reach up and trail feather-light over Castiel’s stomach.  The Omega shakes his head, his own hands coming to rest over his belly.  Dean reaches out and squeezes his fingers, planting a soft kiss to his cheek.

“The doctor did a test, when you were first admitted.  Asked me if there was any chance you were pregnant, and when I said yes, they did a blood test.  It came out positive.”

Tears blur Castiel’s eyes, and when he looks down, he sees that Dean is crying too.  But there is a smile on his face, and when he leans forward to kiss him, he swears he can feel the Alpha’s lips tremble against his own.  “Oh, Dean…,” he breathes, closing his eyes and nuzzling his nose against Dean’s cheek.  “We’re going to be a family.”

A scent of happiness fills the room and Dean smiles, leaning close and resting his head against Cas’s chest.  He kisses him there, right over his heart, and smiles. 

“Yeah, we are.”

**Author's Note:**

> I think there's a bit much going on here. Was it too much? I think I got a bit carried away.  
> Maybe I'll try writing this again some other time when I'm less obsessed with pregnant?!cas...
> 
> Feedback?


End file.
